I'm trying to link to an external worksheet and would like to specify the
cell indirectly. Instead of explicitly referencing the cell I would like to
determine the cell by a formula.

Instead of this:
=[CUBIE.XLS]Sheet1!E5

I would like to calculate "E5" and store it in the current worksheet cell
[H3]. How can I have an external link using this indirect reference? How
different would this look if the external document is open or not?

For example, these attempts did not work:
=[CUBIE.XLS]Sheet1!$H$3]
=INDIRECT("[CUBIE.XLS]Sheet1! & $H$3")

Thanks,
Doug